Object wait notify notifyAll 方法详解

wait()方法表示，放弃当前对资源的占有权，等啊等啊，一直等到有人通知我，我才会运行后面的代码。

notify()方法表示，当前的线程已经放弃对资源的占有， 通知等待的线程来获得对资源的占有权，但是只有一个线程能够从wait状态中恢复，
然后继续运行wait()后面的语句；

notifyAll()方法表示，当前的线程已经放弃对资源的占有， 通知所有的等待线程从wait()方法后的语句开始运行。 读出什么区别没有？
wait，notify，notifyAll方法必须运行在synchronized代码块内

demo

import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.CyclicBarrier;
public class WaitNotifyDemo {
	static final CountDownLatch lath = new CountDownLatch(2);
	static final CyclicBarrier lathb = new CyclicBarrier(2);
	
	private static final Object syncObj = new Object();

	static class WaitThread extends Thread {
		@Override
		public void run() {
			System.out.println("wait begin enter synchronized");
			synchronized (syncObj) {
				try {
					System.out.println("wait start");
					// 线程等待
					syncObj.wait();
					System.out.println("wait end");
				} catch (InterruptedException e) {
					e.printStackTrace();
				}

			}
			try {
				lathb.await();
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (BrokenBarrierException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			lath.countDown();
		}
	}

	static class NotifyThread extends Thread {
		@Override
		public void run() {
			try {
				Thread.sleep(10);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("notify begin enter synchronized");
			synchronized (syncObj) {
				System.out.println("notify start");
				// 当前线程运行完毕后 唤醒wait线程
				syncObj.notify();

				System.out.println("notify end");

			}
			try {
				lathb.await();
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (BrokenBarrierException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			lath.countDown();
		}
	}

	public static void main(String[] args) throws InterruptedException, BrokenBarrierException {

		WaitThread wd = new WaitThread();
		NotifyThread nd = new NotifyThread();
		wd.start();
		nd.start();
		
		//TODO主线程等待子线程的三种法法
		//调用join
		// nd.join();
		// wd.join();
		
		//调用CountDownLatch
		lath.await();
		
		//调用CyclicBarrier
		// lathb.await();
		System.out.println("=============");

	}
}